The Dead Sea Under Michigan That Detroit Is Still Mining

More than a thousand feet under Detroit there's a second city: over a hundred miles of roads, carved out of the salt of a sea that dried up about 425 million years ago. Thirty facts, counting down, from the copper and iron of the Upper Peninsula to a 9,000-year-old hunting trap at the bottom of Lake Huron, to the reason the Great Lakes curl around the mitten: Michigan sits on a stone bowl three miles deep that once held a dying tropical sea. Where are you watching from? If you've found a Petoskey stone, walked the old copper country of the Keweenaw, or your family worked the mines or the salt under Detroit, tell us in the comments. Subscribe to Beneath The States for more places that are hiding something.